Mixing in turbulent flows

在自然界和人造世界中，湍流都是常态（层流是例外）。它们的基础是它们快速混合质量、动量或能量的能力，这是一个广泛过程的基础属性，包括空气动力学、气象学、燃烧和环境污染物扩散。本提案的主要目标是通过原创的创新研究，为湍流中的混合过程提供新的见解。为此，我的长期目标有四个方面：1)进行细致的、最先进的实验，为湍流混合提供新的视角；2)在本科、硕士和博士阶段培养HQP； 3)构思新的实验方法和工具，以开发创新技术，使我的研究小组和整个湍流社区受益；4)提供详细的、为那些模拟和模拟湍流的科学家和工程师提供高质量的湍流测量，以便他们可以验证他们的模拟/模型。为了实现这些长期目标，本申请提出了一套与湍流中标量（如温度、化学物质浓度）混合相关的补充项目。这五个研究项目涉及：1)量化背景湍流对自由剪切流动中混合的影响；2)高雷诺数和psamclet数下的混合；3)湍流中多个标量的同时混合；4)多孔表面/边界上的标量色散；5)冰雪表面上湍流传热的影响。这项研究的结果将与燃烧、环境污染物扩散和气候建模领域的工作人员直接相关。该研究项目还将培训湍流和一般热流体方面的HQP，为当地的航空航天、水电、汽车等行业提供熟练的专业人员。在过去的5年里，我的实验室获得了两个新的实验设备（包括一个新的风洞），并开发了新的仪器（实现了世界上很少有研究小组能够进行的新的复杂测量），现在有可能取得显著的进步。此外，上述研究的结果将回答湍流混合的重要尚未解决的问题。然后应将所获得的知识应用于与能源和环境有关的学科的技术改进（例如，提高燃烧器效率，改进政府对环境污染物扩散的影响评估模式）。

In both nature and the man-made world, turbulent flows are the norm (laminar flows being the exception). Fundamental to them is their capacity to rapidly mix mass, momentum or energy an attribute that underlies a wide range of processes, including aerodynamics, meteorology, combustion, and environmental pollutant dispersion. The main goal of the present proposal is to provide novel insights into the mixing process within turbulent flows by way of original, innovative research. To this end, my long-term objectives are four-fold: 1) to undertake careful, state-of-the-art experiments that will provide new perspectives on turbulent mixing, 2) to train HQP at the undergraduate, master's and doctoral levels, 3) to conceive of new experimental methods and tools for the development of innovative technologies benefitting both my research group and the general turbulence community, and 4) to provide reliable datasets of detailed, high-quality measurements in turbulent flows to those scientists and engineers who simulate and model turbulence, so they can validate their simulations/models. To accomplish these long-term objectives, the present application proposes a complementary set of projects relevant to the mixing of scalars (e.g., temperature, chemical species concentration) in turbulent flows. The five research projects pertain to: 1) quantification of the effect of background turbulence on the mixing within free-shear flows, 2) mixing at high Reynolds and Péclet numbers, 3) simultaneous mixing of multiple scalars within turbulent flows, 4) scalar dispersion over a porous surface/boundary, and 5) the effect of turbulent heat transfer above snow and ice surfaces. The results of this research will be of immediate relevance to workers in the fields of combustion, environmental pollutant dispersion, and climate modelling. The research program will also train HQP in turbulent flows, and thermofluids in general, supplying skilled professionals to the local aerospace, hydropower, automotive, etc. industries. Given the acquisition in the last 5 years of two new experimental facilities in my laboratory (including a new wind tunnel), and the development of novel instrumentation (enabling new sophisticated measurements of which few research groups worldwide are capable), notable advances will now be possible. Moreover, the results of the above studies will answer important unresolved questions about turbulent mixing. The knowledge obtained should then be applied to technological improvements in disciplines related to energy and the environment (e.g., increased combustor efficiencies, improved governmental impact assessment models of environmental pollutant dispersion).